This is the reason why men with facial hair are hotter — could this explain the Mark Zuckerberg ‘beard’ appeal?

Men with beards are hotter — by a hair.

A doctored image of Mark Zuckerberg with sunkissed skin and some scruff broke the internet over the weekend, begging the question: What about men with facial hair is oh-so hot?

“In that pic, he went from a dud to a stud. From a punk to a hunk,” Nnenna B., a New York City content creator, told HuffPost, imploring Zuck to get a beard transplant in Turkey.

Meanwhile, actress Christal Luster told the outlet the Meta founder and CEO “gave big zaddy energy” with a beard, a preference that persists in her own dating life. She told HuffPost that she has reconsidered men she previously rejected men after they grow a beard.

“They looked like teenagers before but when they grew the beard out, I circled the block faster than the ice cream man on a hot summer’s day,” Luster quipped. “Seriously, though, it is a nice addition to a beautiful face. Just matures them for me, I guess.”

A 2016 study found that men with light to heavy stubble are perceived as more attractive than their clean-shaven peers, surveying more than 8,500 women who all preferred the men to have some sort of facial hair.

“It may be because it gives the face more definition in the jawline and enhances perceptions of age and masculinity,” study author Barnaby Dixson, a University of the Sunshine Coast human behavioral ecologist, told HuffPost.

The findings are “not surprising,” said University of New South Wales professor Rob Brooks who was not involved in the study, explaining that “testosterone pathways are so involved in both dominance and facial hair growth.”

But if the beard is the “most obvious sign of dominance,” Brooks mused, why shave it?

“We think it may be to reduce competition and intimidation in the kinds of close-cooperation, within and between sexes, that’s required to make our complex, highly cooperative societies function,” he said.

According to the study, 10-day scruff seemed to be the sweet spot, while grizzly, over-grown beards were less than ideal, which is likely “a hygiene and grooming effort thing that women cue in to,” Brooks added. Not to mention, men’s beards have been found to harbor more bacteria than dog’s fur or even a toilet seat.

New Yorker David Yi, founder of the beauty blog Very Good Light, previously declared the lumberjack growth “dead,” likening well-groomed scruff to makeup on women.

“It’s all about men being conscious about shaping their beards, and ensuring they can make their faces the most chiseled they can be,” he previously told The Post.

For Zuckerberg, growing out a beard might also humanize him.

Canadian content creator Jaks Lark — who tends to match with more singles looking for long-term love on dating apps when he has a beard — told HuffPost that the Facebook mogul could benefit from a bit of stubble, highlighting Zuckerberg’s “public relations struggle,” describing his mannerisms as “robotic.”

A beard, said Lark, would add “a whole new element to his character.”

But musician Samantha Kim, who has a bit of facial hair himself, doesn’t think Zuckerberg needs the scruff.

“His hairless face is already deeply ingrained in our collective subconscious, it looks like he’s cosplaying,” he explained. “But he doesn’t really need a beard to pull because money is a hell of a beard.”